Move Tuple to src-{non-}bootstrapped library

Author: nicolasstucki

library/src/scala/Tuple.scala renamed to library/src-bootstrapped/scala/Tuple.scala

@@ -0,0 +1,217 @@
+package scala
+import annotation.showAsInfix
+import compiletime._
+import internal._
+
+// non-bootstrapped
+
+/** Tuple of arbitrary arity */
+sealed trait Tuple extends Any {
+  import Tuple._
+
+  /** Create a copy this tuple as an Array */
+  inline def toArray: Array[Object] =
+    scala.runtime.Tuple.toArray(this)
+
+  /** Create a copy this tuple as an IArray */
+  inline def toIArray: IArray[Object] =
+    scala.runtime.Tuple.toIArray(this)
+
+  /** Return a new tuple by prepending the element to `this` tuple.
+   *  This operation is O(this.size)
+   */
+  inline def *: [H, This >: this.type <: Tuple] (x: H): H *: This =
+    scala.runtime.Tuple.cons(x, this).asInstanceOf[H *: This]
+
+  /** Return a new tuple by concatenating `this` tuple with `that` tuple.
+   *  This operation is O(this.size + that.size)
+   */
+  inline def ++ [This >: this.type <: Tuple](that: Tuple): Concat[This, that.type] =
+    scala.runtime.Tuple.concat(this, that).asInstanceOf[Concat[This, that.type]]
+
+  /** Return the size (or arity) of the tuple */
+  inline def size[This >: this.type <: Tuple]: Size[This] =
+    scala.runtime.Tuple.size(this).asInstanceOf[Size[This]]
+
+  /** Given two tuples, `(a1, ..., an)` and `(a1, ..., an)`, returns a tuple
+   *  `((a1, b1), ..., (an, bn))`. If the two tuples have different sizes,
+   *  the extra elements of the larger tuple will be disregarded.
+   *  The result is typed as `((A1, B1), ..., (An, Bn))` if at least one of the
+   *  tuple types has a `Unit` tail. Otherwise the result type is
+   *  `(A1, B1) *: ... *: (Ai, Bi) *: Tuple`
+   */
+  inline def zip[This >: this.type <: Tuple, T2 <: Tuple](t2: T2): Zip[This, T2] =
+    scala.runtime.Tuple.zip(this, t2).asInstanceOf[Zip[This, T2]]
+
+  /** Called on a tuple `(a1, ..., an)`, returns a new tuple `(f(a1), ..., f(an))`.
+   *  The result is typed as `(F[A1], ..., F[An])` if the tuple type is fully known.
+   *  If the tuple is of the form `a1 *: ... *: Tuple` (that is, the tail is not known
+   *  to be the cons type.
+   */
+  inline def map[F[_]](f: [t] => t => F[t]): Map[this.type, F] =
+    scala.runtime.Tuple.map(this, f).asInstanceOf[Map[this.type, F]]
+
+  /** Given a tuple `(a1, ..., am)`, returns the tuple `(a1, ..., an)` consisting
+   *  of its first n elements.
+   */
+  inline def take[This >: this.type <: Tuple](n: Int): Take[This, n.type] =
+    scala.runtime.Tuple.take(this, n).asInstanceOf[Take[This, n.type]]
+
+
+  /** Given a tuple `(a1, ..., am)`, returns the tuple `(an+1, ..., am)` consisting
+   *  all its elements except the first n ones.
+   */
+  inline def drop[This >: this.type <: Tuple](n: Int): Drop[This, n.type] =
+    scala.runtime.Tuple.drop(this, n).asInstanceOf[Drop[This, n.type]]
+
+  /** Given a tuple `(a1, ..., am)`, returns a pair of the tuple `(a1, ..., an)`
+   *  consisting of the first n elements, and the tuple `(an+1, ..., am)` consisting
+   *  of the remaining elements.
+   */
+  inline def splitAt[This >: this.type <: Tuple](n: Int): Split[This, n.type] =
+    scala.runtime.Tuple.splitAt(this, n).asInstanceOf[Split[This, n.type]]
+}
+
+object Tuple {
+
+  /** Type of the head of a tuple */
+  type Head[X <: NonEmptyTuple] = X match {
+    case x *: _ => x
+  }
+
+  /** Type of the tail of a tuple */
+  type Tail[X <: NonEmptyTuple] <: Tuple = X match {
+    case _ *: xs => xs
+  }
+
+  /** Type of the concatenation of two tuples */
+  type Concat[X <: Tuple, +Y <: Tuple] <: Tuple = X match {
+    case Unit => Y
+    case x1 *: xs1 => x1 *: Concat[xs1, Y]
+  }
+
+  /** Type of the element a position N in the tuple X */
+  type Elem[X <: Tuple, N <: Int] = X match {
+    case x *: xs =>
+      N match {
+        case 0 => x
+        case S[n1] => Elem[xs, n1]
+      }
+  }
+
+  /** Literal constant Int size of a tuple */
+  type Size[X <: Tuple] <: Int = X match {
+    case Unit => 0
+    case x *: xs => S[Size[xs]]
+  }
+
+  /** Converts a tuple `(T1, ..., Tn)` to `(F[T1], ..., F[Tn])` */
+  type Map[Tup <: Tuple, F[_]] <: Tuple = Tup match {
+    case Unit => Unit
+    case h *: t => F[h] *: Map[t, F]
+  }
+
+  /** Given two tuples, `A1 *: ... *: An * At` and `B1 *: ... *: Bn *: Bt`
+   *  where at least one of `At` or `Bt` is `Unit` or `Tuple`,
+   *  returns the tuple type `(A1, B1) *: ... *: (An, Bn) *: Ct`
+   *  where `Ct` is `Unit` if `At` or `Bt` is `Unit`, otherwise `Ct` is `Tuple`.
+   */
+  type Zip[T1 <: Tuple, T2 <: Tuple] <: Tuple = (T1, T2) match {
+    case (h1 *: t1, h2 *: t2) => (h1, h2) *: Zip[t1, t2]
+    case (Unit, _) => Unit
+    case (_, Unit) => Unit
+    case _ => Tuple
+  }
+
+  /** Converts a tuple `(F[T1], ..., F[Tn])` to `(T1,  ... Tn)` */
+  type InverseMap[X <: Tuple, F[_]] <: Tuple = X match {
+    case F[x] *: t => x *: InverseMap[t, F]
+    case Unit => Unit
+  }
+
+  /** Implicit evidence. IsMappedBy[F][X] is present in the implicit scope iff
+   *  X is a tuple for which each element's type is constructed via `F`. E.g.
+   *  (F[A1], ..., F[An]), but not `(F[A1], B2, ..., F[An])` where B2 does not
+   *  have the shape of `F[A]`.
+   */
+  type IsMappedBy[F[_]] = [X <: Tuple] =>> X =:= Map[InverseMap[X, F], F]
+
+  /** Transforms a tuple `(T1, ..., Tn)` into `(T1, ..., Ti)`. */
+  type Take[T <: Tuple, N <: Int] <: Tuple = N match {
+    case 0 => Unit
+    case S[n1] => T match {
+      case Unit => Unit
+      case x *: xs => x *: Take[xs, n1]
+    }
+  }
+
+  /** Transforms a tuple `(T1, ..., Tn)` into `(Ti+1, ..., Tn)`. */
+  type Drop[T <: Tuple, N <: Int] <: Tuple = N match {
+    case 0 => T
+    case S[n1] => T match {
+      case Unit => Unit
+      case x *: xs => Drop[xs, n1]
+    }
+  }
+
+  /** Splits a tuple (T1, ..., Tn) into a pair of two tuples `(T1, ..., Ti)` and
+   * `(Ti+1, ..., Tn)`.
+   */
+  type Split[T <: Tuple, N <: Int] = (Take[T, N], Drop[T, N])
+
+  /** Convert an array into a tuple of unknown arity and types */
+  def fromArray[T](xs: Array[T]): Tuple = {
+    val xs2 = xs match {
+      case xs: Array[Object] => xs
+      case xs => xs.map(_.asInstanceOf[Object])
+    }
+    scala.runtime.Tuple.fromArray(xs2).asInstanceOf[Tuple]
+  }
+
+  /** Convert an immutable array into a tuple of unknown arity and types */
+  def fromIArray[T](xs: IArray[T]): Tuple = {
+    val xs2: IArray[Object] = xs match {
+      case xs: IArray[Object] => xs
+      case xs =>
+        // TODO support IArray.map
+        xs.asInstanceOf[Array[T]].map(_.asInstanceOf[Object]).asInstanceOf[IArray[Object]]
+    }
+    scala.runtime.Tuple.fromIArray(xs2).asInstanceOf[Tuple]
+  }
+
+  /** Convert a Product into a tuple of unknown arity and types */
+  def fromProduct(product: Product): Tuple =
+    scala.runtime.Tuple.fromProduct(product)
+
+  def fromProductTyped[P <: Product](p: P)(using m: scala.deriving.Mirror.ProductOf[P]): m.MirroredElemTypes =
+    Tuple.fromArray(p.productIterator.toArray).asInstanceOf[m.MirroredElemTypes] // TODO use toIArray of Object to avoid double/triple array copy
+}
+
+/** Tuple of arbitrary non-zero arity */
+sealed trait NonEmptyTuple extends Tuple with Product {
+  import Tuple._
+
+  /** Get the i-th element of this tuple.
+   *  Equivalent to productElement but with a precise return type.
+   */
+  inline def apply[This >: this.type <: NonEmptyTuple](n: Int): Elem[This, n.type] =
+    scala.runtime.Tuple.apply(this, n).asInstanceOf[Elem[This, n.type]]
+
+  /** Get the head of this tuple */
+  inline def head[This >: this.type <: NonEmptyTuple]: Head[This] =
+    scala.runtime.Tuple.apply(this, 0).asInstanceOf[Head[This]]
+
+  /** Get the tail of this tuple.
+   *  This operation is O(this.size)
+   */
+  inline def tail[This >: this.type <: NonEmptyTuple]: Tail[This] =
+    scala.runtime.Tuple.tail(this).asInstanceOf[Tail[This]]
+
+}
+
+@showAsInfix
+sealed abstract class *:[+H, +T <: Tuple] extends NonEmptyTuple
+
+object *: {
+  def unapply[H, T <: Tuple](x: H *: T): (H, T) = (x.head, x.tail)
+}